Registering components in the root component’s components option doesn’t make them global. Doing that just makes them available to the root component itself, not its children.

To register components globally, use app.component in your top-level code:

main.js

import { createApp } from 'vue';
import App from './App.vue';
import MyGlobalComponent from './components/MyGlobalComponent.vue';

const app = createApp(App);
app.component('MyGlobalComponent', MyGlobalComponent); ✅
const mountedApp = app.mount('#app');